I ran a 60" on a 450 Rhino and moved 11" of medium heft snow (not powder, not heavy and wet) with no problem. I wished I'd gotten a 72" for that machine. The General has tons more power and torque than that Rhino did.
When deciding on a width, remember that a 60" blade clears a path for your tires in a straight line but when you angle the blade a 60" isn't wide enough and the tires are now fighting for traction. My $.02
According to Denali, their mount for the RZR fits the General too.
I will find out tomorrow, I'm going to attempt to install my 72" Denali plow I used for the last few years on my RZR 1000, on the General.